736 
1963. Transporting on Pallets (translated title). Obst u. Gemuse 27(6): 
29-36 ° 
74. Woodward, H. C. 
1949, Quality of Maine McIntosh Apples From Orchard to the Consumers. 
Maine Agr. Expt. Sta. Bul. 478, 36 pp. 
WAXES AND SKIN COATINGS 
Many attempts have been made to retard transpiration and fruit metabolism 
by waxing or by various other skin coatings (1, 2, 6, 8, ll, 12). L 
Christopher et al (3) showed the importance of very high humidity in reducing 
moisture losses of apples in cold storage. Often, even with high humidity, 
moisture loss from fruit is excessive during prolonged storage. Werner and 
Kitzke (13) pointed out that waxes, if properly used, can improve appearance, 
reduce moisture loss, respiration, and friction injuries, and serve as carriers 
for fungicides, etc. On apples, waxes and oil coatings are seldom used com- 
mercially. 
Since 1945, Pieniazek and Christopher (10), Linde and Kennard (9), and 
Ford and Alban (4) have shown that wax emulsions can reduce weight loss of 
apples in storage. Pieniazek and Christopher (10) found that the reduction in 
rate of transpiration with wax emulsions of different concentrations was not 
constant through the storage period. A high concentration of wax emulsion in- 
creased the rate of transpiration immediately after application. Later it 
dropped much below that of untreated apples. Golden Delicious apples treated 
with wax emulsions had a better appearance after storage than nontreated fruit. 
Respiration was reduced about 10 percent by the wax treatment, according to 
Ford and Alban (4). 
Hulme (8) and Trout, Hall, and Sykes (12) reported that oil emulsions 
affect storage behavior by modifying the concentration of carbon dioxide and 
oxygen within apples. On the Granny Smith variety, oil coating (castor oil and 
shellac) caused a marked retardation of normal skin yellowing, which is con- 
trolled by the internal oxygen supply (12). ; 
Oil coatings reduced respiration of both pears and apples (11, 12). 
Reyneke and Pearse (11) found that the reduced rate of respiration was accom- 
panied by a reduced rate of acetaldehyde production, which delayed the onset 
of storage scald. Hall, Sykes, and Trout (5) reported that a 7%-percent coating 
of castor oil and shellac reduced scald. They found that the storage life of 
apples in a nonrefrigerated storage was often increased as much as 50 percent 
with oil coatings. The prolonged storage life was attributed to increased car- 
bon dioxide and decreased oxygen in the internal atmosphere (7). Oil coatings 
reduced scald more than the use of controlled-atmosphere storage did. 
Hulme (8) listed three factors affecting the usefulness of oil coatings; 
the maturity and temperature of fruit when coated, the degree of emulsification 
of the skin coating, and the oil concentration in the coating emulsion. 
1/ Underscored numbers in parentheses refer to Literature Cited, p. 35. 
34 
